SSH2: fix E_NOTICE in keyboard interactive code
SSH2: fix E_NOTICE in keyboard interactive code

Thanks ravage84!
paragonie-scott/phpseclib,melya/phpseclib,creatuity/phpseclib,phpseclib/phpseclib,creatuity/phpseclib,thaigialai1987/phpseclib,metaclassing/phpseclib,splitice/phpseclib,danog/phpseclib,danog/phpseclib,kenichiii/phpseclib,ericariyanto/phpseclib,ericariyanto/phpseclib,paragonie-scott/phpseclib,phpseclib/phpseclib-php5,kenichiii/phpseclib,melya/phpseclib,thaigialai1987/phpseclib,metaclassing/phpseclib,splitice/phpseclib,phpseclib/phpseclib-php5,terrafrost/phpseclib